Automatic position-locking tool carrier apparatus and method

Abstract

An automatic position-locking tool carrier apparatus and method include a carriage that rides on a first rail and a second rail translatably connected to the carriage perpendicular to the first rail. Pinion gears that engage with the two rails are attached to the carriage and coupled to position encoders which transmit position signals to a controller. The controller produces control signals to control brake mechanisms coupled to the pinion gears. Translational motion of the carriage and the second rail are limited or prevented when the position of the carriage and the second rail are within predetermined limitations from a predetermined location, fixing the position of an end-effector head attached at one end of the second rail. The carriage and the second rail are propelled by forces external to the system.

What is claimed is: 
     
       1. A device, comprising:
 a first rail having a longitudinal axis; 
 a carriage moveably coupled to the first rail to translate in a direction along the longitudinal axis; 
 a first axle mounted to the carriage and rotationally coupled to the first rail to rotate in proportion to a translational movement of the carriage in a direction along the longitudinal axis; 
 a first encoder coupled to the carriage to create a first position signal based on a rotational position of the first axle; 
 a first brake mechanism coupled to the carriage and to the first axle to selectively inhibit rotation of the first axle; and 
 a controller linked to the first encoder and to the first brake mechanism to control the first brake mechanism in response to the first position signal; 
 wherein the first rail is relatively stiff in bending about a first bending axis and relatively flexible in bending about a second bending axis orthogonal to the first bending axis, and the first rail is releasably attached to a workpiece such that the first bending axis is substantially normal to a workpiece surface and the second bending axis is substantially parallel to the workpiece surface. 
 
     
     
       2. The device of  claim 1 , further comprising:
 a plurality of rotary members coupled to the carriage to engage the first rail to moveably couple the carriage to the first rail. 
 
     
     
       3. The device of  claim 1 , further comprising at least one attachment device to releasably attach the first rail to a workpiece. 
     
     
       4. The device of  claim 3 , wherein the attachment device includes a plurality of vacuum cups coupled to the first rail to attach the first rail to a workpiece. 
     
     
       5. The device of  claim 1 , wherein the controller performs an algorithm using data regarding at least the first position signal corresponding to a first coordination hole and a second coordination hole to shift a predetermined data set with a known orientation with respect to the first and second coordination holes to correspond to an orientation of the first rail with respect to a workpiece. 
     
     
       6. The device of  claim 1 , wherein the controller is preprogrammed with a plurality of data sets and performs an algorithm using data regarding at least the first position signal corresponding to a first coordination hole and a second coordination hole to select a specific data set. 
     
     
       7. The device of  claim 1 , further comprising an input device mounted on the device and linked to the controller to receive user input. 
     
     
       8. The device of  claim 1 , wherein the controller is configured with a data set defining a plurality of predetermined locations where manufacturing processes are to be performed, and the controller is configured to control at least the first brake mechanism in order to successively fix an end-effector head in each of the predetermined locations so that the manufacturing processes can be performed. 
     
     
       9. The device of  claim 8 , further comprising a plurality of visual indicators mounted on the device to indicate a direction in which the device may be moved from its current location toward a next predetermined location. 
     
     
       10. The device of  claim 1 , further comprising:
 a second rail moveably coupled to the carriage to translate with respect to the carriage in a direction of a longitudinal axis of the second rail; 
 a second axle mounted to the carriage and rotationally coupled to the second rail to rotate in proportion to a translational movement of the second rail in a direction along the longitudinal axis of the second rail; 
 a second encoder coupled to the carriage to create a second position signal based on a rotational position of the second axle; and 
 a second brake mechanism coupled to the carnage and to the second axle to selectively inhibit rotation of the second axle; 
 wherein the controller also is linked to the second encoder and to the second brake mechanism and controls the second brake mechanism in response to the second position signal. 
 
     
     
       11. The device of  claim 10 , further comprising:
 a first air-driven axial piston motor coupled to the carriage and to the first axle to propel the carriage; and 
 a second air-driven axial piston motor coupled to the carriage and to the second axle to propel the second rail; 
 wherein the controller also is linked to the first and second axial piston motors and controls the first and second axial piston motors in response to the first and second position signals, respectively. 
 
     
     
       12. The device of  claim 10 , further comprising:
 a plurality of evenly spaced slots laterally aligned along the first rail in the direction of the longitudinal axis of the first rail; 
 a plurality of evenly spaced slots laterally aligned along the second rail in the direction of the longitudinal axis of the second rail; 
 a first pinion gear coupled to the first axle to engage the slots on the first rail such that the first pinion gear rotates in proportion to the translation of the carriage with respect to the first rail; and 
 a second pinion gear coupled to the second axle to engage the slots on the second rail such that the second pinion gear rotates in proportion to the translation of the second rail with respect to the carriage. 
 
     
     
       13. The device of  claim 10 , wherein the controller is configured to determine a first displacement between the carriage and a first predetermined position on the first rail and to modulate a first brake control signal in order to dynamically control a carriage velocity based on the first displacement, and to determine a second displacement between the carriage and a second predetermined position on the second rail and to modulate a second brake control signal in order to dynamically control a second rail velocity based on the second displacement. 
     
     
       14. The device of  claim 10 , wherein the controller is further configured to control a carnage acceleration and a second rail acceleration. 
     
     
       15. The device of  claim 10 , further comprising an end-effector head coupled to the second rail that translates with the second rail in the directions of the longitudinal axes of the first and second rails to carry a tool. 
     
     
       16. The device of  claim 15 , further comprising a drill coupled to the end-effector head. 
     
     
       17. The device of  claim 15 , further comprising a teach button to send a teach signal to the controller when the teach button is actuated, the teach signal indicating that the end-effector head is at a known distance from and a known orientation with respect to a coordination hole at a predetermined location on the workpiece. 
     
     
       18. The device of  claim 15 , further comprising:
 a teach pin associated with the end-effector head to position the end-effector head at a known distance from and a known orientation with respect to a coordination hole at a predetermined location on the workpiece, the teach pin including: 
 a push rod end to facilitate manual depression of the teach pin; and 
 a conical segment at an end opposite the push rod end to engage the coordination hole in order to axially align the teach pin with the coordination hole. 
 
     
     
       19. The device of  claim 18 , further comprising a position sensor to sense the position of the teach pin and send a teach signal to the controller when the teach pin is at a predetermined axial position, the teach signal indicating that the teach pin is aligned with the coordination hole. 
     
     
       20. The device of  claim 15 , further comprising a gravity compensator to compensate for an effect of the weight of the tool due to gravitational force. 
     
     
       21. The device of  claim 15 , further comprising:
 a rail-mount rotatably coupled to the carriage to rotate with respect to the carriage around an axis normal to the longitudinal axes of the first and second rails; 
 a third encoder to create a third position signal corresponding to an angular position of the rail-mount; and 
 a third brake mechanism to inhibit rotation of the rail-mount; 
 wherein the second rail is moveably coupled to the rail-mount to translate with respect to the rail-mount in the direction of the longitudinal axis of the second rail, and the end-effector head further travels in an arc defined by a distance from the axis of rotation of the rail-mount to the end-effector head, and the controller also is linked to the third encoder and to the third brake mechanism and controls the third brake mechanism in response to the third position signal. 
 
     
     
       22. The device of  claim 1 , wherein the brake is concentrically attached to the axle. 
     
     
       23. A tool carrier, comprising:
 means for carrying a tool; 
 means for moveably supporting the carrying means having a longitudinal axis along which the carrying means translates; 
 means for rotating mounted to the carrying means and rotationally coupled to the supporting means to rotate in proportion to a translational movement of the carrying means in a direction along the longitudinal axis; 
 means for sensing a rotational position of the rotating means to create a position signal; 
 means for braking coupled to the carrying means and to the rotating means to selectively inhibit rotation of the rotating means; and 
 means for controlling linked to the sensing means and to the braking means to control the braking means in response to the position signal; 
 wherein the supporting means is relatively stiff in bending about a first bending axis and relatively flexible in bending about a second bending axis orthogonal to the first bending axis, and the supporting means is releasably attached to a workpiece such that the first bending axis is substantially normal to a workpiece surface and the second bending axis is substantially parallel to the workpiece surface. 
 
     
     
       24. A method of positioning a tool, comprising the steps of:
 moveably supporting a carriage on a rail having a longitudinal axis along which the carriage translates; 
 sensing a rotational position of an axle that is mounted to the carnage and rotationally coupled to the rail to rotate in proportion to a translational movement of the carriage in a direction along the longitudinal axis; 
 creating a position signal based on the sensed rotational position of the axle; 
 controlling a first brake mechanism coupled to the carriage and to the axle in response to the position signal; and 
 selectively inhibiting rotation of the axle with the brake mechanism; 
 wherein the rail is relatively stiff in bending about a first bending axis and relatively flexible in bending about a second bending axis orthogonal to the first bending axis, and the rail is releasably attached to a workpiece such that the first bending axis is substantially normal to a workpiece surface and the second bending axis is substantially parallel to the workpiece surface. 
 
     
     
       25. The method of  claim 24 , further comprising the steps of:
 sensing a position of a second rail with respect to the carriage; 
 controlling a second brake mechanism in response to the second rail position; and 
 selectively inhibiting movement of the second rail with the second brake mechanism.